Any discussion of the background art throughout the specification should in no way be considered as an admission that such background art is prior art, nor that such background art is widely known or forms part of the common general knowledge in the field.
Absorption spectroscopy is widely used to qualitatively and quantitatively identify chemical species. If a species of interest possesses a unique absorption feature, real-time monitoring of the absorber can be achieved by simply measuring absorbance at a single frequency, or over a single absorption band. However, more often than not, contaminants are present which also absorb light of the same frequency. As a result, real-time spectral analysis of contaminated samples requires collection of absorbance data over a range of wavelengths.
Unfortunately, this approach is commonly hindered by the ability to rapidly extract information from complex absorption data.
Therefore, there is a need for a demodulation technique to extract absorption information from time-varying absorption signals in real time, or at least significantly faster than current spectral analysis systems.